A monitor capable of assisting in operating a working machine such as an excavator and allowing an operator to perform maintenance of the working machine is mounted beside of a driver's seat of the working machine, and in many cases, the monitor is disposed in a deep front side of a cab (the right front side seen from the operator) (for example, see Patent Literatures 1 and 2).
In such a monitor, a rear-view camera image obtained with a rear-view monitor camera of a working machine may be displayed (for example, see Patent Literature 3).
Such a monitor has physical select switches of a working machine. In order to prevent an operator of the monitor from operating a display switch by mistake during execution of tasks so that information that is not related to the tasks is displayed to make the operator bewildered, some monitors allow a specific display screen to be selectable only in an idling state so that the screen is not displayed even when the select switch is pressed in a task execution state (for example, see Patent Literature 2).
Moreover, a working machine monitor which employs a touch panel monitor which uses a touch panel as an input device is known (for example, see Patent Literature 4).
Patent Literature 1: Japanese Patent Application Publication No. 2005-188156
Patent Literature 2: Japanese Patent Application Publication No. 2005-307483
Patent Literature 3: Japanese Patent Application Publication No. 2008-202331
Patent Literature 4: Japanese Patent Application Publication No. 2002-173956